Fuel economy=bad. Power and reliability=good. Do a search on here and you will see the constant complaint most 6 liter owners have is the mileage. I have one in a 02 1500HD and it gets 10-11 towing and 15-16 under ideal conditions. That is with 3.73 gears. The newer trucks have a 5 or 6 speed auto which might help a little, but the 6.0 is a thirsty engine.

The 6.0 is definitley a relaible motor. The fuel economy is terrilble though. I have one as a daily driver. The 6.0 tends to turn alot of rpms to make it power too, I'm not sure why GM has it set up this way, but def. not a bad motor.

I'm pushing more toward a GM 2500 6.0L V8 myself. No 3ton HD gas truck is going to get decent mileage empty or pulling a trailer. I have a 5.9L V8 in my Durango and the engine is gold. I get about 10mpg towing 3500lbs in town.

Oh, if you pick up the latest Truck Trend it has the Silverado up against the Ford (and GMC Sierra, although it's the same truck..). It gave the GM trucks tops for best performance and mileage over the Ford 6.2L mostly because the Ford gas weighs 400lbs more in similar configuration. The Silverado/Sierra averaged mid 13mpg during the testing including a short towing stint. The Ford 6.2 was in the 12mpg. Not too far off, but weight is the ultimate factor in determining fuel economy. Both have 6 speed auto's.

The GM trucks with 3.73 gears and the gas engine in top gear at 60mph turned 1700rpm apparently, which seems to be a comfortable cruising speed but add on a plow, salter, or trailer for that matter and the 4.10 gears will knowingly return better mileage and offer less gear hunting. Decisions decisions....

I've got an '07 (new body style) Chevy 2500HD ext cab/short bed with the 3:73 gears and 6.0L gas engine. I think it does pretty good on fuel, you can't be too hard on the throttle, but with a fairly light foot you can achieve pretty good fuel economy.

In the city I can get around 12-13mpg. On the highway I can get just over 17mpg doing about 70mph. If I'm doing 55mph I can actually get just over 20mpg. Now, when it comes to towing, I get about 8-10mpg depending on the load and whether I'm doing more city or highway type driving. Usually I'm towing a 2880lb trailer with 2000lb mower and some grass, so probably 5500lbs. On an average tank of towing, city and highway driving I get 12 mpg.

The 6.0 Vortec has tons of power and I have found it to be quite fuel efficient for an HD truck.

I have 3 of those engines in the truck department. Great motors. Will tow with the diesel trucks but always shifting. Empty truck on HWY we can get around 15-18 Trailer and empty - 12 - 14 . loaded 8-10

My theroy is if you need the truck - fuel shouldn't be a major concern. Its meant for work, hauling, pulling, etc. Not driving to church - although maybe it will go to church but not as the family vehicle - but then again??

That's just it. A vehicle is what it is, it has a purpose. Family car is just that, a transportation appliance for the masses. A truck is meant for work and daily activities. A HD truck is meant for harder work and therefor weighs more, eats more fuel, costs more to maintain and so on. Mileage shouldn't matter unless you plan to use it to commute.

I realize everyone is attempting to save a few bucks where they can. If you want to get better mileage get a ScanGauge that plugs into the diagnostic port. It shows you instant fuel economy readout so you can be more cautious on the throttle. However, when towing or hauling that goes out the window.

i just traded my 09 6.0 liter silverado in for a 2011 duramax dieasel wow i should have done this a long time ago ,,what a truck will never own a gas job again i can surely justify the 8000$ dollar option for the duramax and the allison automatic,,,go test drive one youll deffinetly want one

i just traded my 09 6.0 liter silverado in for a 2011 duramax dieasel wow i should have done this a long time ago ,,what a truck will never own a gas job again i can surely justify the 8000$ dollar option for the duramax and the allison automatic,,,go test drive one youll deffinetly want one

Maintenance costs will catch up to you in the long run. The thing I don't like about the 100K warranty on the 6.6L is that even for simple warranty repairs you still have to pay $100 or something like that for each visit.... nuts!